At least one example embodiment of the inventive concepts relates to an image sensor, and more particularly, to an image sensor capable of boosting a voltage of a floating diffusion node and/or an image processing system including the same.
An image sensor is a device that converts an optical image into an electrical signal and may be used in digital cameras and other image processing devices.
Image sensors include a pixel array including a plurality of pixels. Each of the pixels includes a photoelectric conversion element that performs photoelectric conversion, a transfer transistor that transmits charges generated by the photoelectric conversion element to a floating diffusion node, a reset transistor that resets the floating diffusion node, a source follower that operates in response to the charges at the floating diffusion node, and a select transistor that transmits signals output from the source follower to a column line.
A gate of the source follower is connected to the floating diffusion node. In order to increase the amount of charges that can be stored at the floating diffusion node, an operating voltage applied to pixels or a capacitance of the floating diffusion node is increased. However, the increase of the operating voltage applied to pixels may lead the increase of the power consumption of an image sensor including pixels and the increase of the capacitance of the floating diffusion node may lead the increase of the size of pixels. Therefore, these methods are not appropriate for image sensors requiring high resolution and low power consumption.